Answer:
She planned to go by herself!
Explanation:
After working for the Pittsburgh Dispatch for a few years, Bly got the dangerous assignment to infiltrate the infamous asylum from Joseph Pulitzer himself, after she blustered her way into his offices, according to Kroeger's book
Careful is already a adjective so keep that.
There are many adjectives for change but what suits the best here is “changing”.
Careful changing is the best I could find.
Hope that helped